Why is there no isWatchSource utility?

[DerZade]

When writing composables it's always nice to use MaybeRefOrGetter. But if I then want to use watch in that composable, I always have to check if it is actually a valid watch source:

import { watch, type MaybeRefOrGetter } from 'vue';

function useMyComposable(input: MaybeRefOrGetter<string>) {
  watch(input, (val) => { // this will warn if `input` is neither a `Ref` nor a getter
    // do something with input
  });

  // do something with input
}

Would be nice to have a isWatchSource utility similar to isRef or isReactive:

import { watch, type MaybeRefOrGetter, isWatchSource } from 'vue';

function useMyComposable(input: MaybeRefOrGetter<string>) {
  if (isWatchSource(input)) watch(input, (val) => {
    // do something with input
  });

  // do something with input
}

[DerZade]

This is my impl. of isWatchSource that I use atm, but I'm sick of copying it to every new project 😂

/**
 * Checks if a value is a valid watch source.
 * @param val The value to check if it is a watch source.
 * @returns True if the value is a watch source, false otherwise.
 */
function isWatchSource<T>(
  val: MaybeRefOrGetter<T | null>,
): val is WatchSource<T | null> {
  if (isRef(val)) return true;
  if (isReactive(val)) return true;
  if (typeof val === 'function') return true;
  return false;
}